New jet feature in the parsec-scale jet of the blazar OJ287 connected to the 2017 teraelectronvolt flaring activity
R. Lico, C. Casadio, S. G. Jorstad, J. L. Gomez, A. P. Marscher, E. Traianou, J. Y. Kim, G. Y. Zhao, A. Fuentes, I. Cho, T. P. Krichbaum, O. Hervet, S. O'Brien,… 展开作者
R. Lico, C. Casadio, S. G. Jorstad, J. L. Gomez, A. P. Marscher, E. Traianou, J. Y. Kim, G. Y. Zhao, A. Fuentes, I. Cho, T. P. Krichbaum, O. Hervet, S. O'Brien, B. Boccardi, I. Myserlis, I. Agudo, A. Alberdi, Z. R. Weaver, J. A. Zensus
In February 2017 the blazar OJ287, one of the best super-massive binary-black-hole-system candidates, was detected for the first time at very high energies (VHEs; E>100GeV) with the ground-based gamma-ray observatory VERITAS. Very high energy gamma rays are thought to be produced in the near vicinity of the central engine in active galactic nuclei. For this reason, and with the main goal of providing useful information for the characterization of the physical mechanisms connected with the observed teraelectronvolt flaring event, we investigate the parsec-scale source properties by means of high-resolution very long baseline interferometry observations. We use 86 GHz Global Millimeter-VLBI Array (GMVA) observations from 2015 to 2017 and combine them with additional multiwavelength radio observations at different frequencies from other monitoring programs. We investigate the source structure by modeling the brightness distribution with two-dimensional Gaussian components in the visibility plane. In the GMVA epoch following the source VHE activity, we find a new jet feature (labeled K) at about 0.2 mas from the core region and located in between two quasi-stationary components (labeled S1 and S2). Multiple periods of enhanced activity are detected at different radio frequencies before and during the VHE flaring state. Based on the findings of this work, we identify as a possible trigger for the VHE flaring emission during the early months of 2017 the passage of a new jet feature through a recollimation shock (represented by the model-fit component S1) in a region of the jet located at a de-projected distance of about 10 pc from the radio core.
Characterizing Gamma-Radio Delayed Flaring Activity from Blazars
MSU（密歇根州立大学）；ELTE Eötvös Loránd University（罗兰大学）；HUN-REN Research Centre for Astronomy and Earth Sciences（匈牙利研究与创新天文学与地球科学研究中心）；University of Wisconsin—Madison（威斯康星大学麦迪逊分校）
Exceptional Gamma-Ray Flaring Activity of the Blazar S4 0954+65 in Early 2025
Shanghai Normal University（上海师范大学）；Sun Yat-sen University（中山大学）；Yunnan Observatories（云南天文台）；National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台）
Constraining the Physical Conditions in the Jets of Gamma-Ray Flaring Blazars using Centimeter-Band Polarimetry and Radiative Transfer Simulations. I. Data and Models for 0420-014, OJ 287, and 1156+295
Finnish Centre for Astronomy with ESO (FINCA)（芬兰ESO天文学中心）；University of Turku（图尔库大学）；Aalto University（阿尔托大学）；Max-Planck-Institut für Astronomie（马克斯·普朗克天体物理学研究所）；National Centre for Radio Astrophysics (NCRA) - Tata Institute of Fundamental Research (TIFR)（国家射电天文中心（NCRA）- 塔塔基础研究院（TIFR））；European Southern Observatory（欧洲南方天文台）；Nordic Optical Telescope（北欧光学望远镜）；Aarhus University（奥胡斯大学）
First Combined Study on LIV from Observations of Energy-dependent Time Delays from Multiple-type Gamma-ray Sources -- Part I. Motivation, Method Description and Validation through Simulations of H.E.S.S., MAGIC and VERITAS Datasets
Observational Study of Multi-wavelength Synergistic Effects in 3C 120
State Key Laboratory of Radio Astronomy and Technology, Xinjiang Astronomical Observatory, Chinese Academy of Sciences（中国科学院新疆天文台射电天文与技术重点实验室）；School of Astronomy and Space Science, University of Chinese Academy of Sciences（中国科学院大学天文学与空间科学学院）；Changchun Observatory, National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台长春观测站）；Department of Physics and Astronomy, College of Physics, Guizhou University（贵州大学物理学院物理学与天文学系）
The spectrum of the persistent radio source associated with FRB 20190417A
Istituto Nazionale di Astrofisica - Istituto di Radioastronomia（意大利国家天体物理研究所射电天文研究所）；South African Radio Astronomy Observatory（南非射电天文台）；Centre for Radio Astronomy Techniques and Technologies (RATT), Department of Physics and Electronics, Rhodes University（罗德斯大学物理与电子学院射电天文技术与方法中心）；Istituto Nazionale di Astrofisica - Osservatorio Astronomico di Cagliari（意大利国家天体物理研究所卡利亚里天文台）；Dipartimento di Fisica e Astronomia - Università di Bologna（博洛尼亚大学物理与天文学系）；Scuola Universitaria Superiore IUSS Pavia（帕维亚高等大学）
